WO2010112743A1

WO2010112743A1 - Use, as a shock absorber, of a material formed from branched molecules containing associative groups

Info

Publication number: WO2010112743A1
Application number: PCT/FR2010/050567
Authority: WO
Inventors: Manuel Hidalgo; Nicolas Dufaure; Jean-Luc Couturier; Bruno Van Hemelryck
Original assignee: Arkema France
Priority date: 2009-04-02
Filing date: 2010-03-29
Publication date: 2010-10-07
Also published as: EP2414427A1; JP2012522860A; FR2944025A1; CN102365311A; US20120022221A1; US8975363B2; JP5695024B2; CN102365311B; KR20110132420A; EP2414427B1; FR2944025B1

Abstract

The present invention relates to the use, as a shock absorber, of a material formed from branched molecules comprising associative groups. Said branched molecules are each constituted of fragments that are at least bifunctional and of fragments that are at least trifunctional joined together by ester or thioester bridges, alone or in combination with amide or urea bridges.

Description

Use as a shock absorber of a material consisting of tree molecules having associative groups

The present invention relates to the field of shock absorbing materials, and more particularly to the use as a shock absorber, of a material formed of tree molecules comprising associative groups. Shock absorbing materials are well known to those skilled in the art. Mention may be made, in general, of thermoplastic elastomeric materials such as block copolymers such as SBC (styrene block copolymers) or thermofixes (vulcanized) such as crosslinked natural rubber or synthetic rubber such as BR, SBR, NBR (butadiene). "Rubber", styrene-butadiene "rubber", nitrile butadiene "rubber"). Mention may be made, more particularly from these materials, of copolymers based on EVA, polynorbornenes or even polyurethanes. These materials have many applications, such as structural elements of shoe soles, gloves, bulletproof vests, shooting targets including arrows, bullets, darts, but also coatings for tool handles, carpets ground, or anti-vibration elements.

Because of these many possible applications, there is a permanent need for new products capable of absorbing shocks, that is to say having good damping properties.

The subject of the invention is therefore the use, as impact absorber, of a specific material formed of tree molecules having associative groups.

This specific material contains molecules having a particular tree structure conferring them damping properties, which can vary according to the proportion of the reagents used for their synthesis, as well as other properties. Thus, as a function of the number of reactive functions present on the initial compounds and the number of reactive functions remaining after the first synthesis step, these numbers are easily adjusted by the choice of raw materials and by the Using a suitable stoichiometric ratio, it is possible to obtain, in a controlled manner, a semi-crystalline or amorphous solid, a viscoelastic liquid or an optionally thermoplastic elastomer material. More specifically, when the average functionality of the monomers is low, essentially linear molecules having a viscoelastic behavior and possibly having a semicrystalline or amorphous solid phase are produced, while forming networks possibly comprising an insoluble fraction and exhibiting elastomeric properties when this functionality is high. It is thus possible to obtain materials having not only a good ability to absorb shocks but also a compromise of properties such as good self-repair ability, good creep resistance, good fluidity when they are put in place. implemented.

By "use as a shock absorber" of a material as defined above, it will be understood within the meaning of the invention a capacity utilization damping of the specific material as defined above, containing molecules having a tree structure.

Damping means in the sense of the invention a damping as measured by the tangent delta (also called loss factor) of the material, greater than or equal to 0.5, or preferably greater than 1, at the temperature of use . Said delta tangent being calculated as the ratio of the dynamic loss modulus (in shear or elongation, G '' or E '') and conservation (in shear or elongation, G ', E'). These dynamic modules are obtained by dynamic mechanical analysis measurements (acronyms in English DMA) or by dynamic measurements in a rheometer at frequencies greater than 50 Hz, and preferably greater than or equal to 100 Hz. measures is well known in the art and has been widely described in the literature, for example in the book "Viscoelastic Properties of polymers" by JD Ferry, ^3rd edition, Wiley, 1980.

The terms "shock absorbing" must be understood in a broad sense, that is both as capable of absorbing and dissipating the kinetic energy created for example by sound waves, or by the shock between an object any and the specific material defined above. This term must also be understood in the sense of an overall anti-vibration effect.

It is also possible to obtain a material having not only shock absorption properties, but also the properties of a thermoplastic elastomer, that is to say a material capable, at ambient temperature, of being able to be subject to uniaxial deformation, advantageously at least 20% for 15 minutes, then recover, once the stress is relaxed, its initial dimension, with a remanent deformation less than 5% of its initial dimension, and which can be put or reformed at high temperature. It has furthermore been observed that this material can be self-healing, that is to say capable, once cut, torn or scratched, to be repaired by simply bringing the fractured surfaces into contact without the need to heat or apply significant pressure or perform any chemical reaction, the repaired material retaining elastomeric properties.

The material can be obtained by a process consisting in reacting, in a first step, a first compound containing a high proportion of at least trifunctional molecules on a second compound carrying one or more associative groups, in non-stoichiometric proportions allowing to subsist free functions on the first compound, to obtain a material which is reacted, in a second step, with an at least bifunctional compound.

The subject of the present invention is therefore the use, as impact absorber, of a material comprising tree molecules each consisting of at least bifunctional fragments and at least trifunctional fragments united to one another by ester or thioester bridges. , alone or in combination with amide or urea bridges, said bridges being formed from two functions carried by different fragments, said molecules further comprising, on the fragments located at the ends of the trees, terminal associative groups capable of associate with each other by links hydrogen and covalently connected to functions not participating in said bridges.

According to a preferred embodiment of the invention, this material is capable of being obtained according to the process comprising the following successive steps:

(a) the reaction of at least one at least trifunctional compound (A) carrying first and second functions with at least one compound (B) bearing, on the one hand, at least one reactive group capable of reacting with the first functions of (A) and, on the other hand, at least one associative group;

(b) reacting the compound (s) obtained in step (a) with at least one at least one bifunctional compound (C) whose functions are capable of reacting with the second functions of the compound (A) to form ester or thioester bridges, alone or in combination with amide or urea bridges.

By "tree" is meant according to the invention a branched molecule whose backbone has at least two branches. This definition does not exclude that various branches of the same molecule can join together to form loops.

It is possible that a fraction of the tree molecules according to the invention is insoluble both in water and in any organic solvent.

By "associative groups" is meant groups capable of associating with each other by hydrogen bonds, advantageously by 1 to 6 hydrogen bonds. Examples of associative groups that can be used according to the invention are the imidazolidonyl, triazolyl, triazinyl, bis-ureyl and ureido-pyrimidyl groups. It is preferred that the average number of terminal associative groups per molecule of the material is at least 3. It is advantageously at most 6. These are covalently linked to the molecule. By "covalently" is meant that the associative groups are connected to the terminal functions of the molecule either via a direct bond or, preferably, via a chain, especially alkylene.

By "reactive groups" or "functions" is meant chemical functions capable of reacting with other chemical functions to form covalent bonds, leading in particular to the formation of ester, thioester, amide, urea or urethane bridges and in particular ester and amide bridges. A "bifunctional" compound refers to a compound having two identical or different reactive functions. An "at least trifunctional" compound refers to a compound carrying at least three identical or different reactive functions.

By "fragment" is meant in the sense of the invention a unit of a molecule located between two or three bridges as defined above. A "bifunctional" moiety is obtainable from a bifunctional compound and a "trifunctional" moiety is obtainable from a trifunctional compound. The tree molecules according to the invention comprise at least bifunctional fragments, advantageously bifunctional, and at least trifunctional fragments, advantageously trifunctional. The compound (A) used in the first step of the process according to the invention may in particular carry at least three identical or different functions chosen from acid, ester or chloride functions. acyl. It advantageously comprises from 5 to 100, preferably from 12 to 100 and more preferably from 24 to 90 carbon atoms.

The compound (A) may, in the first step of the process according to the invention, be in admixture with mono- and bifunctional compounds, such as mono- and diacids, in particular fatty acid mono- and dimers.

It is preferred to use trimers (oligomers of 3 identical or different monomers) and mixtures of dimers and trimers of fatty acids of vegetable origin. These compounds result from the oligomerization of unsaturated fatty acids such as: undecylenic, myristoleic, palmitoleic, oleic, linoleic, linolenic, ricinoleic, eicosenoic, and docosenoic acid, which are usually found in pine oils

(TaIl oil fatty acids), rapeseed, maize, sunflower, soybean, grape seed, flax, jojoba, as well as the eicosapentaenoic and docosahexaenoic acids found in fish oils.

Examples of fatty acid trimers which may be mentioned are the compounds of the following formulas which illustrate the cyclic trimers derived from fatty acids with 18 carbon atoms, given that the compounds available commercially are mixtures of steric isomers and isomers of position of these structures, possibly partially or totally hydrogenated.

C18 acid trimer

It is thus possible to use a mixture of fatty acid oligomers containing dimers, trimers and monomers of linear or cyclic Cis fatty acids, said mixture being predominant in dimers and trimers and containing a small percentage (usually less than 5% ) of monomers. Preferably, said mixture comprises:

0.1 to 40% by weight, preferably 0.1 to 5% by weight of identical or different fatty acid monomers, 0.1 to 99% by weight, preferably 18 to 85% by weight of dimers of the same or different fatty acids, and

0.1 to 90% by weight, preferably 5 to 85% by weight, of identical or different fatty acid trimers.

Examples of dimeric / trimeric mixtures of fatty acids (% by weight) are:

• Pripol® 1017 from Uniqema, a mixture of 75-80% of dimers and 18-22% of trimers with about 1-3% of monomeric fatty acids,

• Uniqema's Pripol® 1048, a 50/50% dimers / trimer blend, • Uniqema Pripol® 1013, a mixture of 95-98% dimers and 2-4% trimers with a maximum of 0.2% of monomeric fatty acids,

• Uniqema Pripol® 1006, a mixture of 92-98% dimers and up to 4% trimers with a maximum of 0.4% of monomeric fatty acids,

• Uniqema's Pripol® 1040, a blend of dimers and trimers of fatty acid with at least 75% trimers and less than 1% monomeric fatty acids, • Unidyme® 60 from Arizona Chemicals, a mixture of 33% dimers and 67% trimers with less than 1% monomeric fatty acids,

• Unidyme® 40 from Arizona Chemicals, a blend of 65% dimers and 35% trimers with less than 1% monomeric fatty acids,

• Unidyme® 14 from Arizona Chemicals, a mixture of 94% dimers and less than 5% trimers and other higher oligomers with about 1% monomeric fatty acids, • Empol® 1008 from Cognis, a blend of 92% dimers and 3% higher oligomers, essentially trimers, with about 5% monomeric fatty acids,

Empol® 1018 from Cognis, a mixture of 81% of dimers and 14% of higher oligomers, essentially of which trimers, with about 5% of monomeric fatty acids,

• Oleon's Radiacid® 0980, a mixture of dimers and trimers with at least 70% trimers.

Pripol®, Unidyme®, Empol®, and Radiacid® products include Cis fatty acid monomers and oligomers of fatty acids corresponding to multiples of

Cl8 •

According to one variant of the invention, instead of triacids, it is possible to use as compound (A) a compound containing at least three ester or acyl chloride functions.

By way of example of an ester, mention may be made of a methyl, ethyl or isopropyl (preferably methyl) ester of a fatty acid trimer or a mixture of oligomers of fatty acids as defined above. .

In another variant, the compound (A) may be an at least trifunctional compound containing at least two different functions, advantageously chosen from acid, ester and acyl chloride functions.

For its part, the compound (B) carries at least one reactive group which may in particular be selected from primary or secondary amine groups or alcohol. Alternatively, the compound (B) can carry at least two such identical or different groups.

In the case where the reactive group of the compound (B) is capable of reacting with both the first and second functions of the compound (A), it is preferred that, in the first step of the process according to the invention, the ratio of number of the reactive groups of the compound (B) to the sum of the functions of the compound (A) ranges from 0.1 to 0.8 and preferably from 0.3 to 0.8. Compound (B) can thus satisfy any one of formulas (B1) to (B3):

(Bl)

(B2)

(B3) wherein: R denotes a unit containing at least one primary or secondary amine group or alcohol, R 'denotes a hydrogen atom,

A denotes an oxygen or sulfur atom or an -NH group, preferably an oxygen atom.

Preferred examples of compounds (B) are 2-aminoethylimidazolidone (UDETA), 1- (2 - [(2-aminoethyl) amino] ethyl) imidazolidone (UTETA), 1- (2- {2- [2 aminoethylamino] ethyl} amino) ethyl] imidazolidone (UTEPA), 3-amino-1,2,4-triazole and 4-amino-1,2,4-triazole.

By way of example of a compound that can be obtained after the first step of the process described above, mention may be made of:

• UDe 1008 from the reaction between Empol®1008 and UDETA; • I / UDe 1060 resulting from the reaction between Unidyme® 60 and UDETA;

• UDe 1060/1008 resulting from the reaction between Empol®1008, Unidyme® 60 and UDETA; • UDe 1017 resulting from the reaction between Pripol® 1017 and UDETA;

• UDe 1048 resulting from the reaction between Pripol® 1048 and UDETA;

• UDe 1014 resulting from the reaction between Unidyme® 14 and UDETA;

• UDe 1040 resulting from the reaction between Pripol® 1040 and UDETA;

• UDe 0980 resulting from the reaction between Radiacid® 0980 and UDETA.

Depending on the starting fatty acid, a compound which can be semi-crystalline with a melting temperature (T _f ) most often between

30 and 150 ⁰ C and which has a glass transition temperature (T _g ) most often between -50 ⁰ C and 20 ⁰ C.

This compound is then reacted, in the second step of the process according to the invention, with an at least bifunctional compound (C), such that the functions of (C) react with the second functions, ie say the remaining reactive functions of the compound (A). It will be avoided in this step to be placed under catalytic conditions likely to lead to homopolymerization of the compound (C). The compound (C) carries at least two functions, identical or different, chosen in particular from the epoxy, alcohol and amine functions.

Compound (C) is preferably a diepoxide. It can thus be chosen from: bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, tetrabromo bisphenol A diglycidyl ether, or hydroquinone diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, butylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, resorcinol diglycidyl ether, neopentyl glycol diglycidyl ether, bisphenol A polyethylene glycol diglycidyl ether bisphenol A polypropylene glycol diglycidyl ether, diglycidyl ester of terephthalic acid, epoxidized polyunsaturated fatty acids, and epoxidized limonene; and their mixtures.

Alternatively, the compound (C) may be a polyepoxide containing at least three epoxide functions, chosen for example from: castor oil triglycidyl ether, 1,1,1-tris (hydroxymethyl) propane triglycidyl ether, trisphenol triglycidyl ether, glycerol tridlycidyl ether, glycerol propoxylate triglycidyl ether, glycerol ethoxylate triglycidyl ether, trimethylol propane triglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritolpolyglycidyl ether, poly (glycidyl acrylate), polyglycidyl methacrylate fatty acids epoxidized polyunsaturates, epoxidized vegetable oils, epoxidized fish oils and mixtures thereof.

In another variant, the compound (C) may be a diol. In this case, the compound (C) may be chosen from: ethylene glycol, propylene glycol, tetramethylene glycol, hexamethylene glycol, octanediol, nonanediol, decanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyesters with hydroxy ends, polybutadienes with hydroxy ends, polydimethylsiloxanes with hydroxy ends, polyisobutylenes with hydroxy ends, polybutadiene-co-acrylonitrile copolymers with ends hydroxy, diol dimers derived from fatty acids and mixtures thereof.

According to another possibility, the compound (C) may be a polyol containing at least three alcohol functions. Examples of such compounds are in particular: sugars such as sorbitol, pentaerythritol, trimethylolpropane, as well as glycerol and its ethoxylated and propoxylated derivatives, castor oil and diol dimers derived from fatty acids such as Pripol 2033 from Uniqema.

It is understood that the material according to the invention comprises binding bridges, preferably amide, formed in the first step of its synthesis process, by reaction of the reactive groups (advantageously primary or secondary amine) of the compound (B) with functions reactive, so-called "first functions" (advantageously, acid functions), the compound (A) and bonding bridges (advantageously ester), formed in the second step of this process, by reaction of the remaining reactive functional groups (preferably acidic), called "second functions", of the compound ( A) with reactive functions (advantageously epoxy) of the compound (C). This material also contains hydrogen bonds between the associative groups carried by the molecules that constitute it. The presence of these reversible hydrogen bonds, which can be broken by a rise in temperature and to be reformed at room temperature, allows the material according to the invention to have a melt flow which is sufficient to be converted by well-known methods. known to those skilled in the art (injection, molding, extrusion ...) and possibly a large elongation at break at room temperature, without it having a high molecular weight.

The tree molecules constituting said material contain a soluble fraction, as well as possibly an insoluble fraction, that is to say a fraction representing from 0.1 to 90% of the weight of the material and which is not soluble in any proportion in no solvent. The number-average molecular weight of the soluble fraction is preferably from 300 to 300,000 g / mol, as measured by GPC.

According to one embodiment of the invention, the average number of terminal associative groups per molecule is at least 1.2, preferably at least 2, or even at least 2.2. It is furthermore understood that this material may contain molecules other than the tree molecules described above, in particular in the case where the compound (A) contains trimers of fatty acids mixed with mono- and / or dimers of fatty acids. . Advantageously, the material according to the invention contains at least 25% and more preferably at least 50% by number of said tree molecules.

It is preferred according to the invention that this material also contains intermolecular hydrophobic bonds, advantageously due to interactions between alkyl groups carried by each of the tree molecules described above. By "alkyl" is meant in the sense of the invention side groups (C _n H _{2n +} i) and not alkylene chains (C _n H _2n ), for example. In a particularly preferred manner, each of these molecules comprises C6-C24 alkyl chains, advantageously in greater number than said terminal associative groups. They may in particular be provided by the compounds (A), in particular when they are trimers of fatty acids.

The compounds (A), (B) and (C) described above can be introduced, in the process according to the invention, in the molten state or by the solvent route.

The proportions of (A), (B) and (C) used in the process according to the invention determine the mechanical characteristics of the material according to the invention. The material as defined above has high shock absorption capabilities over a wide temperature range.

It thus preferably has a Delta tangent greater than 0.5, at a frequency of at least 50 Hz, and preferably greater than or equal to 100 Hz, over a temperature range of from 20 to 50 ^° C. and even, for example, certain materials over a temperature range of -5 ⁰ C to 80 ⁰ C or more.

Advantageously, the material furthermore has elastomeric properties, that is to say the property of being able to undergo uniaxial deformation at ambient temperature and to recover, once this stress is relaxed, its initial dimension, with a lower remanent deformation. at 10% and preferably less than 5% of its initial dimension, according to the deformation initially applied.

It is furthermore preferred that the material according to the invention has self-repairing properties. By this term is meant the capacity of the material, after a cut such as that resulting from an elongation up to break or such as that performed by scissors or other cutting or shearing tool, or any other method of cutting without contact as the laser cut, followed by a contact at room temperature of the faces of the material where the rupture occurred, to be soldered and to be again subjected to traction. As recalled above, the proportions and the nature of (A), (B) and (C) used in the process according to the invention determine the mechanical characteristics of the material according to the invention.

It is therefore preferred that the material according to the invention is such that: the compound (A) is a trimer of at least one of the following acids: undecylenic acid, myristoleic acid, palmitoleic acid, oleic acid, linoleic acid, linolenic acid, ricinoleic acid, eicosenoic acid, docosenoic acid, eicosapentaenoic acid and docosahexaenoic acid, the compound (B) is chosen from: aminoethylimidazolidone (UDETA), 1- (2 - [(2-aminoethyl) amino] ethyl) imidazolidone (UTETA), 1- (2- {2 - [(2-aminoethylamino] ethyl} amino) ethyl] imidazolidone (UTEPA) , 3-amino-1,2,4-triazole and 4-amino-1,2,4-triazole, and the compound (C) is chosen from: bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, tetrabromo bisphenol A diglycidyl ether, or hydroquinone diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, butylene glycol diglycidyl ether , neopentyl glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, resorcinol diglycidyl ether, neopentyl glycol diglycidyl ether, bisphenol A polyethylene glycol diglycidyl ether, bisphenol A polypropylene glycol diglycidyl ether, diglycidyl ester terephthalic acid, castor oil triglycidyl ether, 1,1,1-tris (hydroxymethyl) propane triglycidyl ether, trisphenol triglycidyl ether, glycerol tridlycidyl ether, glycerol propoxylate triglycidyl ether, glycerol ethoxylate triglycidyl ether , trimethylol propane triglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritolpolyglycidyl ether, poly (glycidyl acrylate), polyglycidyl methacrylate, epoxidized polyunsaturated fatty acids, epoxidized vegetable oils, epoxidized fish oils, epoxidized limonene and mixtures thereof

The shock absorbing capacities of the material can be adjusted by the choice of the compound C, for a given proportion of the compounds A, B and C. Thus, the shock absorption capacities of the material are very important when the compound C is selected from: epoxidized soybean oil, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether.

The material may in particular be used to manufacture any type of object intended to absorb shocks or vibrations, such as buffers and bumpers for land vehicles, in particular trains, trucks, cars, trolleys including forklifts, but also boat guards, play mats, bullet-proof vests, shooting targets including arrows, balls, and darts, sports protections including leg protectors, elbow guards, gloves, gaskets for suits sports helmets and protective helmets, protection elements for pipes and to make objects for dissipating the energy created by sound waves, such as noise-reducing coatings.

In these applications, the material according to the invention can be used as such or in single-phase or multiphase mixtures with one or more compounds such as petroleum fractions, solvents, mineral and organic fillers, plasticizers, resins and the like. tackifiers, antioxidants, pigments and / or dyes, for example, in emulsions, suspensions or solutions.

The invention will be better understood in the light of the following examples, given for purposes of illustration only, and which are not intended to limit the scope of the invention, defined by the appended claims.

The invention is also illustrated by FIG. 1 which represents the evolution of the delta tangent of the products of example 4 (HR) and of example 5 (HM) as a function of the temperature at ⁰ C for a shear at

150 Hz.

EXAMPLES

Example 1 Preparation of a material according to the invention

In a 4 liter glass reactor equipped with a mechanical stirrer, a temperature probe, a nitrogen inlet via a dip tube, a dropping funnel, a Dean Stark surmounted by a condenser and 1300 g of a trimer of fatty acids (Pripol 1040, acid number = 188 (mg of KOH / g), or 4.36 mol of acid functions) were introduced into a heating mantle. 299 g of 2-aminoethylimidazolinone (UDETA, alkalinity number = 7.3 meq / g, 2.18 mol, 0.5 equivalents) in the molten state were introduced into the dropping funnel. The reactor was heated to 80 ^° C., then, with stirring and under a flow of nitrogen, the UDETA was cast over a period of 10 minutes. The temperature was gradually raised to 180 ^° C. over a period of 4 hours, then allowed to react for 2 hours at 180 ^° C. The amount of water recovered was 39 g (2.18 mol). It was allowed to cool to 130 ° C to recover 1475 g of a brown viscous liquid which solidified at room temperature. The acid number (mg KOH / g of product needed to neutralize the acid groups) of the product obtained was 67.5 mg KOH / g.

7.5g was then placed in the product in a PTFE beaker of diameter 5 cm, with 1.73 g of Araldite ^® LY556 (DGEBA epoxy prepolymer with an average number of hydroxyl groups per molecule of n = 0.15 is a number average molecular weight Mn = 382.6). After heating the cup at 150 ^° C., the mixture was homogenized using a spatula and then poured into a PTFE mold with a diameter of 8 cm, held for 1 hour at 150 ^° C. and then 48 hours at 125 ° C. The mold was then cooled to room temperature. After demolding, a flexible film of material said RH-4, thickness about 1 mm in the center was obtained. After cutting with a razor blade, it was found that this film was repaired spontaneously when the pieces were brought into contact within a period of less than one hour. Example 2 Preparation of a Material According to the Invention

The procedure was the same as in Example 1 using 1625 g of Pripol ^® 1040 (acid number = 188 mg KOH / g, or 5.46 mol of acid functions) and 224.4 g of UDETA. (1.64 mol, 0.3 equivalents). 26.5 g of water (1.64 mol) and 1770 g of a brown viscous liquid which solidified at room temperature were recovered. The acid number of the product was 105.8 mg KOH / g.

7,75g was then placed in the product in a PTFE mold of diameter 8 cm, with 2.8 g of Araldite ^® LY556. After heating the mold at 150 ⁰ C, the mixture was homogenized using a spatula, maintained for 1 hour at 150 ⁰ C and 48 hours at 125 ° C. The mold was then cooled to room temperature. After demolding, a flexible film having a thickness of about 1.5 mm in the center was obtained. After cutting with a razor blade, it was found that this film was repaired spontaneously when the pieces were brought into contact within a period of less than one hour.

Example 3 Preparation of a material according to the invention

In a 50 ml three-necked flask equipped with a magnetic heating stirrer, a gas inlet and a connection allowing evacuation, was poured 5, 62 g of dimer / trimer mixture of acid Unidyme ^® 60 and 1.40 g of 2-aminoethylimidazolidinone (UDETA) of molar purity greater than 95%. The mixture, swept with a stream of nitrogen, was heated at 180 ^° C. for 12 hours. Regularly, a light vacuum was applied with a water pump to remove water dissolved in the medium. The liquid mixture was cooled to 150 ^° C., then 1.91 g of Araldite LY556 epoxy resin was added. After 45 minutes of residence at 150 ° C., the mixture was poured into a PTFE mold with a diameter of 8 cm and placed in an oven at 125 ° C. for 48 hours.

The sample obtained after demolding was in the form of an elastic film of 1.6 mm thick.

Example 4 Preparation of a material according to the invention

In a Schott reactor of useful volume 4000 ml, placed on an electric balloon heater and equipped with a temperature probe, a mechanical stirring with a mobile anchor type poly tetrafluoroethylene, a dropping funnel, a condenser condenser, a Dean-Stark and a nitrogen inlet ending with a plunger rod poly tetra fluoroethylene, 1000 g of Pripol® 1040 Uniqema® (acid number 186), or 3 32 moles of carboxylic acid and 245 g of UDETA at 87.6% purity by weight (1.66 moles of amine). It is assumed that the impurities of the UDETA can provide the equivalent of 0.13 mol extra. The mixture is heated at 170 ^° C. to eliminate the condensation water. When the water of condensation is eliminated and trapped in the Dean-stark, the medium is cooled to 80 ^° C. At 80 ^° C., 294 g of a DGEBA epoxy resin, Epikote® 828 EL, are added. Resolution® (epoxy level of 5.2 mol / kg), ie 1.53 mol and is stirred at 80 ⁰ C for 15 minutes. The product thus obtained is emptied from the reactor and may be stored without cooking in polypropylene jars. To obtain the final shock-absorbing material, oven cooking at 120 ^° C. for 24 hours is carried out, preferably in a layer 5 mm thick, in a non-adherent support, such as trays coated with poly tetrafluoroethylene.

Example 5 Preparation of a material according to the invention

In a Schott reactor of useful volume 4000 ml, placed on an electric balloon heater and equipped with a temperature probe, a mechanical stirring with a mobile anchor type poly tetrafluoroethylene, a dropping funnel, a condenser condenser, a Dean-Stark and a nitrogen inlet terminating in a polytetrafluoroethylene plunger rod are charged with 1000 g of Uniogema Pripol® 1040 (acid number 186), ie 3, 32 moles of carboxylic acid and 245 g of UDETA at 87.6% purity by weight, ie 1.66 moles of amine). It is assumed that the UDETA impurities can provide the equivalent of 0.13 mol extra. The mixture is heated at 170 ^° C. to eliminate the condensation water. When the condensation water is removed and trapped in the Dean-stark, the medium is cooled to 120 ° C. At 120 ^° C., 414 g of Arkema's Ecepox® PB 3 epoxidized soybean oil (epoxide level of 3.7 mol / kg), ie 1.53 mol, are added and the mixture is stirred at 120 ^° C. for 15 minutes. The product thus obtained is emptied from the reactor and can be stored without cooking in polypropylene pots. To obtain the final hybrid elastomeric material, oven cooking at 120 ^° C. for 48 hours is carried out, preferably in a layer 5 mm thick, in a non-adherent support, such as trays covered with poly tetra fluoroethylene. The product is sticky and may be talcated on the surface to facilitate its handling and in particular the measurement of mechanical properties.

Example 6 Mechanical Tests

Dumbbell-shaped test pieces with the following dimensions: total length: 35 mm, total width: 6.5 mm, length of the central zone: 10 mm, width of the central zone: 2 mm, thickness: 1.6 mm, were obtained by punching with a punch of the film obtained in Example 3.

- The tensile tests were performed at 25 ° C using a tensile testing machine Instron ^®, equipped with a 10 N load cell at a speed of 2mm / min They gave the following results:

Deformation at break: 427%

Stress at break: 0.65 MPa

Using the same machine, a test of non-elastic strain at elongation was carried out at 25 ^° C. as follows: the specimen was marked with two lines on either side of the central zone, the image of the The test specimen was recorded using a scanner with a resolution of 600 dpi and the distance between the two lines was measured on the image, then the specimen was subjected to an elongation at a speed of 2 mm / min to a deformation of 200%. Then, the 200% deformation was maintained for 1 hour. After this, the test piece was detached from the jaws and then left standing for 12 hours at 25 ° C. The distance between the two lines was then measured again in the same manner as before.

Distance between lines before elongation: 12.5 mm Distance between lines after elongation 12.9 mm or a remanent deformation of 3%.

- Self-repair tests at 25 ° C were performed as follows: the specimen was first cut in the center with a razor blade. After a time t1, both surfaces were brought into contact manually. It was found that they immediately adhered to one another. The test piece was then left standing for a time t2. After which, a tensile test to failure was performed under the conditions mentioned above.

The following results were recorded:

This example shows that after self-healing, the sample was again able to withstand considerable deformations before failure. This example also shows that the quality of self-healing improves as time t2 increases.

Example 7 (comparative) Synthesis and mechanical properties of a material

In a 100 mL flask equipped with a magnetic stirrer and a heating bath, was placed 3.82 g of Araldite LY556 epoxy resin + 5.60 g of acid trimer Unidyme ^® 60. The mixture was heated at 160 ^° C. with stirring until it became miscible and then poured into a PTFE mold with a diameter of 80 mm and finally put in an oven at 125 ° C. for 48 hours. A flexible film having a thickness of about 1.35 mm was obtained. Infrared spectroscopy showed:

a disappearance of the band V _{c =} o of the acid at 1707 cm ^-1

a disappearance of the band V _a of the epoxy at 914 cm ^-1

an appearance of the V _{c =} o band of the ester at 1736 cm ^-1

On this film, the mechanical tests were carried out under the same conditions as above.

The tensile test gave the following results: Elongation at break: 195% Breaking stress: 5.5 MPa

A self-repair test was carried out at 25 ° C in the same manner as in Example 4.

With the times ti = 10 minutes and t2 = 3 hours, the following results were recorded: Elongation at break: 5.1% Maximum stress before rupture: 0.07 MPa.

This example shows that the property of self-repair is not observed in the case of a network consisting of macromolecules chemically crosslinked but lacking intermolecular hydrogen bonds.

Example 8 Synthesis and Mechanical Properties of a Material According to the Invention

In a 500ml Schott reactor equipped with a mechanical stirrer, a condenser, a Dean-Stark, of a nitrogen inlet, a dropping funnel and a temperature probe, 150 g of Pripol 1040 were introduced.

(Uniqema provenance, acid number = 188, or 0.504 mol of acid functions). After heating to 80 ^° C., 36.5 g of UDETA were introduced via the dropping funnel.

(source Arkema, alkalinity index = 6, 9 meq / g,

0.252 mol of amine functions). After heating at 160 ^° C. for 5 hours under a stream of nitrogen, the water formed in Dean-Stark was removed. The temperature was then allowed to drop to 145 ° C., then 62.9 g of epoxidized soybean oil (Ecepox PB1, from Arkema, epoxide number = 4 mmol / g, ie 0.252 mol of epoxide functional groups) were added and allowed to react for 15 minutes at 145-150 ^° C. The reaction mixture was poured into a Teflon ^® tray, which was placed in an oven at 120 ^° C. for 40 hours.

The product thus obtained was sprinkled with talc to better allow handling and demolding the tray. Once the product demolded, the other surface (the one in contact with the tray) was talced in turn. Ribbons 8 cm long by 1 cm wide and 2 mm thick were cut to perform mechanical tests. Pencil marks 4 cm apart were made on the sample (2 cm on each side of the center in length). The sample was then manually deformed until the marks were 14 cm apart, which corresponded to a deformation of 250%. The sample was placed on a table and its springback was observed. 5 minutes after releasing the sample, the distance between the marks had returned to 4.2 cm. Half an hour later, the sample had completely recovered its dimensions of origin and the distance between the marks had returned to 4 cm, which corresponded to 0% of residual deformation.

This example illustrates the elastomeric properties of the materials according to the invention.

Example 9 Impact Absorption Properties of a Material According to the Invention

Measurement of the damping behavior of the product obtained according to Example 4 (HR) and the product obtained according to Example 5 (HM) according to Tan Delta at 150 Hz (high frequency representative of the stress encountered by a material during the fall of an object on its surface)

The measurements of the dynamic mechanical modules making it possible to calculate tan delta as the ratio G '' / G 'were carried out using a DMA Q800 of TA Instruments, the tests were carried out in shear, from 80 ⁰ C to 0 ⁰ C while cooling to 2 ° C / min.

The result of this measurement is shown in Figure 1.

It is found that from -7 ° C. to at least 80 ^° C., the product according to Example 5 (HM) has a delta tangent greater than 0.5. For the product according to Example 4

(HR), tangent delta is greater than 0.5 from

9 ° C, up to at least 80 ^° C.

Claims

1. Use as a shock absorber, of a material comprising tree molecules each consisting of at least bifunctional fragments and at least trifunctional fragments united to each other by ester or thioester bridges, alone or in combination with amide or urea bridges, said bridges being formed from two functions carried by different fragments, said molecules further comprising, on the fragments located at the ends of the trees, terminal associative groups capable of associating with each other by means of hydrogen bonds and covalently connected to the functions not participating in said bridges.

2. Use according to claim 1, characterized in that a fraction of the tree molecules is insoluble.

3. Use according to claim 1 or 2, characterized in that the soluble fraction of said tree molecules has a number average molecular weight of between 300 and 300,000 g / mol.

4. Use according to any one of claims 1 to 3, characterized in that said tree molecules further comprise each of the C6-C20 alkyl chains, preferably in greater number than said terminal associative groups.

5. Use according to any one of claims 1 to 4, characterized in that it contains at least 25% and preferably at least 50% by number of said tree molecules.

6. Use according to any one of claims 1 to 5, characterized in that the associative groups are selected from imidazolidonyl, triazolyl, triazinyl, bis-ureyl, ureido-pyrimidyl.

7. Use according to any one of claims 1 to 6, said material being obtainable by the method comprising the following successive steps:

(a) the reaction of at least one at least trifunctional compound (A) carrying first and second functions with at least one compound (B) bearing, on the one hand, at least one reactive group capable of reacting with the first functions (A) and, on the other hand, at least one associative group, preferably in a ratio by number of the reactive groups of the compound (B) to the sum of the first functions of the compound (A) ranging from 0.1 to 0 , 8 and preferably from 0.3 to 0.8;

8. Use according to claim 7, characterized in that:

the compound (A) carries at least three functions, identical or different, chosen from acid, ester or acyl chloride functions,

the compound (B) carries at least one reactive group chosen from the primary or secondary amine groups or alcohol, and

the compound (C) carries at least two identical or different functions chosen from epoxy, alcohol and amine functions.

9. Use according to claim 7 or 8, characterized in that the compound (A) is a trimer of fatty acid of vegetable origin.

10. Use according to any one of claims 7 to 9, characterized in that the compound (B) corresponds to the formula (Bl), (B2) or (B3):

(Bl

(B2:

(B3) where: R denotes a unit containing at least one primary or secondary amine group or alcohol, R 'denotes a hydrogen atom,

A denotes an oxygen or sulfur atom or an -NH group, preferably an oxygen atom.

11. Use according to claim 8, characterized in that the compound (B) is chosen from: 2-aminoethylimidazolidone (UDETA), 1- (2- [(2-aminoethyl) amino] ethyl) imidazolidone (UTETA), the 1- (2- {2- [(2-aminoethylamino] ethyl} amino) ethyl] imidazolidone (UTEPA), 3-amino-1,2,4-triazole and 4-amino-1,2,4-triazole .

12. Use according to claim 8, characterized in that the compound (C) is chosen from: bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, tetrabromo bisphenol A diglycidyl ether, or hydroquinone diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, butylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, resorcinol diglycidyl ether, neopentyl glycol diglycidyl ether, bisphenol A polyethylene glycol diglycidyl ether, bisphenol A polypropylene glycol diglycidyl ether, diglycidyl ester terephthalic acid, triglycidyl ether castor oil, 1,1,1-tris (hydroxymethyl) propane triglycidyl ether, trisphenol triglycidyl ether, glycerol rol tridlycidyl ether, glycerol propoxylate triglycidyl ether, glycerol ethoxylate triglycidyl ether, trimethylol propane triglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritolpolyglycidyl ether, poly (glycidyl acrylate), polyglycidyl methacrylate, epoxidized polyunsaturated fatty acids, epoxidized vegetable oils, epoxidized fish oils and epoxidized limonene and mixtures thereof.

13. Use according to claim 8, characterized in that the compound (C) is chosen from: ethylene glycol, propylene glycol, tetramethylene glycol, hexamethylene glycol, octanediol, nonanediol, decanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyesters with hydroxy ends, polybutadienes with hydroxy ends, polydimethylsiloxanes with hydroxy ends, polyisobutylenes with hydroxy ends, copolymers polybutadiene-co-acrylonitrile with hydroxy ends, diol dimers derived from fatty acids and mixtures thereof.

14. Use of a material according to any one of claims 1 to 13 for manufacturing objects selected from buffers and bumpers for land vehicles, including trains, trucks, cars, trolleys including forklifts , boat guards, play mats, bullet-proof vests, shooting targets including arrows, balls, and darts, sports protections including legguards, elbow guards, and gloves, sporting suits and protective helmets, protection elements for pipes and ducts and soundproofing coatings.